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Year,.... pros and cons

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Lkario01

New member
Hi, I got my hands on a 115 hp mercury, serial number 45687222. What year is this, and is it a popular model for outboard enthusiasts. Pros and cons? Many thanks , Lou, new member
 
Looks like a 77 model.------Many folks like those motors.------Hopefully you are well versed in doing your own repairs and trouble shooting.------Look at / examine all the wiring as there were issues with bad insulation.-----It is 40 years old no telling what condition it is in.-----Install a new water pump impeller before you launch the boat !
 
Hey Racerone, the insulation on the internal harness had perished when i first inspected it so you are spot on . When I replace it, i will take 'onboard' your suggestion and will order a new water pump impeller too. I haven't got any experience with working on outboards, but I do like learning and fixing things myself so along with my comprehensive workshop manual, I am looking forward to starting this project, When finished, the outboard will be bolted to a black streaker fish/ski boat which will have a strengthened transom to cope with this beastly looking.machine. ....I anticipate a quick boat. I appreciate your reply Racerone . Cheers
 
What are the results of a compression test ?-----Once you have run it for a while there are a number of things to keep an eye on.-----Make sure no water gets into the gear oil.-----Perhaps check and see if the " bleed inserts " are all there.---They ( 5 of them )) are found behind transfer port covers.-----I usually find 2 or 3 missing.
 
Before you spin it over for compression test, (or even hook up a battery), make sure no wires are shorted. The stator, or any ignition wires, if shorted or grounded could cost you plenty troubles.
 
No I havent connected a battery to it yet, thou all the wiring is there ......once the wiring is ok, I'll do a compression test and post the number. I'll.check that all the bleed inserts are in place, and when its ready to start from a service perspective (as guided by my service manual), i will run it for a while and pay particular attention to see if water is in the gear oil.. Wont be rushing this project due to money priorities going elsewhere atm and time availability , but i will continue to update the situation as progress is made. I appreciate your comments too Timguy. Cheers
 
LK, keep us posted, we learn from your experiences too. I'm sure its been idle awhile so you can spray some mixed fuel into the carbs with plugs still in and plug wires off. Why? You get lube onto the bearings as well as into the cylinders. Next, remove plugs and do your compression test. You may notice better numbers with chokes and throttle butterflies somewhat opened. It supports natural entrance of air into the cylinders, rather than entrance from the exhaust side. There are a couple avenues of thought here as for producing the most accurate compression numbers. If you try both ways, (butterflies closed and butterflies opened) we can learn from that to see if there really is a difference on these big bad Mercs. Thanks, Tim
 
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Yes, will keep you posted and will do what I can to facilitate learning both ways. As a point of interest, the outboard, hydraulics and ignition came from a deceased estate. It had been purchased 'some years ago' as a spare setup, As far as I know, it hasn't been pulled apart or started by the previous owner.
 
Hey guys. ......slowly making progress....i replaced the internal harness , it's well lubed internally and i've cranked it over. I do have an issue with the coil which spark/shorts everytime I turn on the ignition via the key. I need this sorted before i compression test it and then start it. I havent tested the coil yet but I suspect it will need to replace it.

So the question I have is is there any advantage in going for an aftermarket 'performance' coil vs a good used mercury coil , which i have already sourced locally. Thanks

Looking forward to starting it soon
 
I, personally don't see an advantage over a good OEM coil. At this stage we need a compression test and that can be done even with the coil as it is. Don't want you to put much money into it if it's gonna need an overhaul and could even have other problems. How does it look? Can you post some photos? You have to reduce the photo file size to around 1000 k. Click on "go advanced" below, then on the paper clip up above that will appear. It seems some smart phones won't work for this, gotta use your laptop. I use Lit photo to start a new file for smaller photos to use here.
 
That all makes sense Timguy. l'll post results of the compression test by the end if the week along with pics. Regarding the engine, it looks fairly clean, all the moving bits were greased and it has had gaskets replaced sometime in the ? recent pas. Internal loom condition has been the only sig issue to date so I am optimistic at the mo that she's gonna breath again with some TLC. We'll see.........
 
Okay, we will stand by, I have a pretty good feeling this could be a good motor too.
 
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